Lubricant



Patented Feb. 24, 1942 LUBRICANT John S. Yule, Chicago, 111., assignor to The Pure i1 Company, Chicago, 111., a corporation of No Drawing. 7 Application December 28, 1940, Serial No. 372,185

22 Claims.

'this invention relates to improvements in lubricants and more particularly to the method of improving mineral oil lubricants and to the product resulting therefrom.

Mineral lubricating oils, during use in internal combustion engines, tend to oxidize and corrode the bearings. The extent of corrosion varies with the type of bearing, the character of service and temperature to which the oil is subjected, and the particular oil used. Solvent refined Pennsylvania oils appear to be more corrosive than other oils which are not solvent refined, apparently due to the fact that the solvents remove natural inhibitors from the oil.

In addition to forming acids and corroding bearings, the oil has a tendency to form sludge and varnish which deposit on the various parts of the engine and not only cause faulty operation of the valves and other working parts, but in some cases cause sticking to such an extent that the motor entirely fails to operate. Such deposits are particularly apt to form when make-up oil is added to the engine. The make-up oil precipitates sludge and varnish from suspension orsolution in the oil in the crankcase.

In order to prevent bearing corrosion and sludge and varnish formation in internal combustion engines, it has been proposed to add oxidation inhibitors to inhibit oxidation, and detergents to keep sludge and varnish dispersed in the oil and prevent it from depositing on the working parts of the motor. This invention is concerned with a novel inhibitor which has the ability to greatly inhibit oxidation of lubricating oil during use and reduce bearing corrosion.

It is known that phosphorized and sulfurized fatty oils and other fatty bodies have the ability of imparting extreme pressure characteristics to mineral oil lubricants when added thereto in amounts ranging upwardly from approximately 5%. I have'now discovered that when compositions of this nature are added to mineral oil bastion engines which is inhibited against hearing corrosion and varnish formation.

It is still another object of this invention to provide a method of lubricating internal combustion engines with mineral lubricating oil in the presence of a novel oxidation inhibitor.

It is still a further object of this invention to minimize. bearing corrosion and varnish formation in automotive engines.

Other objects of the invention will become apparent from the following detailed description.

In accordance with the invention, fatty bodies, including the higher boiling fatty acids and esters thereof, preferably fatty esters of low unsaturation such as rape seed, cotton, lard, sperm and other vegetable, animal or marine oils and waxes, are sulfurized and phosphorized. The method for accomplishing the sulfurization and phosphorization of the fatty body and the characteristics of the resulting products are described in the patent to William A. Whittier, Norman D. \Rilliams and Harry L. Moir, No. 2,211,306. It will be understood, however, that there are other methods of preparing a sulfurized and phosphorized fatty body and that the composilubricants in relatively small amounts-that is,

in amounts below that required to increase loadcarrying ability of the oil to the extent necessary for use in connection with operation of tion contemplated by this invention includes sulfurized and phosphorized fatty bodies which may contain other elements such as chlorine and/or nitrogen. For example, in preparing the sulfurized and phosphorized fatty bodies, sulfur chloride may be used entirely as the sulfurizing agent instead of elemental sulfur and the reaction may be carried out under such conditions that both sulfur and chlorine remain combined with the fatty body and the resulting composition is then phosphorized. This can be done by adding from 3% to 15% by volume of sulfur chloride to the fatty body, maintaining the mixture between and F. until the exothermic reaction ceases, and then maintaining the mixture between 275 and 300 F. until it shows a good copper strip corrosion test. The resulting product is then'phosphorized as set forth in Patent No. 2,211,306. This method of sulfochlorinating and phosphorizing fatty bodies is described in Whittier et al., application Serial Number 353,840.

When the sulfurized and phosphorized fatty material is added to mineral oil lubricants which normally have a tendency to corrode bearing surfaces and to oxidize and form acid, sludge and varnish in the motor, the corrosion, acid, sludge and varnish formation tendencies are remarkably inhibited The effect of the sulfurized-phosphorized base is particularly noticeable in connection with lubricating oils under high temperature or other severe operating conditions, particularly in connection with highly refined Pennsylvania base lubricating oils. Such oils are known to exert harmful corrosion under such conditions of operation on silver-cadmium, copper-lead and some other types of bearings. How-- ever, the'invention is not limited to the use of the sulfurlzed-phosphorized base in connection with such oils since it has been found to have inhibiting properties in connection with practically all known types of lubricating oils.

In order to demonstrate the ability of the sulfurized-phosphoriz'ed fatty body to inhibit corrosion, sludge and varnish formation, various blends were subjected to Underwood.- corrosion tests. Experience has shown that the Underwood machine correlates actual service results rather closely. The Underwood test is described in an article entitled, "Automotive bearing ma- Table II Neat. Na the Chloroform Soluble M01] N o. iDSO I I IbIB soluble sludge Per cent Per cent Per cent 180 vis. ncut 0.0 0.07 0. 04 0. 17 180 vis. neut.+0.l2%

iron naphthenate 0. 09 0. 125 0. 07 0. 20

method D183-27T.

terials and their application, by A. F. Underwood, Journal of Society of Automotive Engi- I iigezers, volume 43, pages 385-392 (September,

A series of Underwood tests was run on straight 180 viscosity Pennsylvania neutral oil alone and to which was added diiierent amounts of. the sulfurized and phosphorized lard oil inhibitor, indicated as S-P lard oil, and sulfochlorinated and phosphorized lard oil, indicated as S-Cl-P lard 011, made as hereinbefore described. This series of tests was also run for five hours at 325 F. with 10#/sq. in. gauge oil pressure using .12% of iron naphthenate containing 0.01% by weight of iron calculated as F6203 as an oxidation catalyst to accelerate the tests. The results are given in Table I.

Table I Loss in wt. Loss in wt. Neut. N a htha, Ag. Cd. Brg. Cu. Pb. Brg. No. insoluble Grams Grarrx Fe cent 180 v15. Pa. neut. 0. 796 r 0. 080 11. 9 r 1.62 0.5% S-P lard Oil. 0.036 0. 038 1. 5 0. 67 1.0% S-P lard Oil. 0.012 0. 015 2. 1 0. 52 1.5% 5-1 lard 011. 0. 003 0. 015 1. 1 0. 46 2.0% S-P lard oil. 0. 0003 0. 002 1. 3 0. 32 2.5% S-P lard oil. 0. 005 0. 014 0. 91 0. 62 3.0% S-P lard Oil. 0. 003 0. 011 0. 4 0. 31 5-11: 1mg 0. 031 0. 51 0. 16 ar 01 0.080 0. 4

S-Cl-P lard 8 0 17 01 O. 0058 0. 0620 0. 60 3.0%, S-Cl-P lard 0 4 o 0. 0009 0. 0048 0. 51 5.0% S-Cl-P lard 0 12 Oil 0. 0033 0. 0238 0. 70 0. 52

. Chloroiorm Soluble Addmve soluble sludge Per 0 n P 180 vis. Pa. neut 1. 24' H 0.5? 8-1 18rd oil. 0. 36 1. 09 1.0 0 5-? lard oil. 0. 29 1. 89 1.5% S-P lard oil. 0.13 1.32 2.0% S-P lard oil 0. 13- 1.28 2.57 8-1 lard oil 0. 23 1. 3.0% 8-1 lard oil. 0.09 0. 57 5.0% S-P lard oil. 0. 04 1.28 7.0% S-P lard oil. O. 04 2. 06 1.0% 01 S-CI-P lard o 0. 33 0. 51. 3.07 of S-Cl-P lard o1 0.03 0.62 5.0% of S-Cl-P lard oil 0. 2a 1. 10

The 180 vis. Pennsylvania neutral was examined prior to being run on the Underwood machine and gave the results indicated in Table II:

The naphtha insoluble chloroform soluble and soluble sludge are determined as follows:

Naphtha insoluble (insoluble sludge) Three grams of theoil is mixed in an Erlenmeyer flask with cc. of A. S. T. M. precipitation naphtha, of the type specified in A. S. T. M.

Chloroform soluble The chloroform soluble is extracted from the dried and weighed naphtha insoluble" residue by pouring successive portions of chloroform through the filter pad using light suction. 100 cc. of chloroform is generally sumcient but the extraction should be continued until the filtrate is colorless. (With heavy naphtha insoluble residues the chloroform is allowed to stand in the crucible without suction for a few minutes before each portion of the chloroform is drawn through the crucible.)

The residue is then dried in an oven at 300 F. for 30 minutes, cooled and weighed. The loss in weight is chloroform soluble.

The solubility in chloroform of the residue from the naphtha. insoluble" determination is affected by the time and temperature of drying. For this reason, in order to secure check results in the chloroform soluble determination, the drying time and temperature, especially in the "naphtha insoluble determination, should be carefully controlled. g

It usually happens that in the Underwood test there is no particular dimculty in filtering, regardless of whether the oils contain detergents or not. However, when these methods areapplied to used crankcase oils it sometimes happens that oils which contain. detergents will not give a clear filtrate. Under these conditions, the illtrate is refiltered through a second Gooch filter and the deposits from both crucibles added in reporting naphtha insoluble (and chloroform soluble).

Propane soluble (soluble sludge) The filtrate from the naphtha insoluble is concentrated to 20 cc. by evaporation and is trans- R. P. M., equivalent to 60 miles per hour.

ferred quantitatively to the extraction apparatus described in Industrial 8: Engineering Chemistry, April 15, 1939, page 183. The remaining naphtha is now completely removed from the oil sample by evaporation on a. steam bath. The propane extraction is carried out as directed in the abovementioned article. The propane insoluble material remaining is calculated in percentage and reported as soluble sludge.

It will be seen that the corrosion of both the silver-cadmium and copper-lead bearings was materially decreased by addition of the sulfurized-phosphorized fatty body and that the acid forming, sludge and varnish-forming tendencies were likewise remarkably decreased. The eifectiveness of the S-P lard oil base was particularly noticeable when added in the proportion of from 2% to 3% by volume. The oil containing 2% of the base was the least corrosive, whereas the oil containing 3% of the base formed the least amount of acidQvarnish andsludge. The optimum amount of additive is, therefore, between 23% by volume. Approximately 3% also appears to be the optimum for the S-Cl-P lard oil inhibitor. No advantage is gained by exceeding 5% by weight of the inhibitor since both corrosion and sludge formation are less below than above 5%.

A series of tests were also made on blends of straight 180 viscosity Pennsylvania neutralwith 30 with no oil change during the entire test. The test is started with 5 quarts of oil. I

In starting the test, the engine is run for about 10 minutes at 2000 R. P. M. and 15 to horsepower until the oil reaches 150 F. The speed is then increased to 3150 R. P. M. and run until the oil temperature reaches 280 F., at which time the test is considered to have begun. Oil is added one quart at a time as needed, but no oil is added during the last 400 miles, or 6% hours of the run.

From Tables Ill and IV it will be observed that by proper balancing of the amount of detergent and inhibitor added to the oil, bearing corrosion can be considerably reduced below that amount which occurs when straight oil or oil plus detergent only are used. The tables also show that although the bearing loss of the oil containing inhibitor and detergent was less than in the case of the straight oil without both inhibitor and detergent, the loss in weight of the bearings as well as the neutralization number, naphtha insoluble, chloroform soluble and soluble sludge were all higher in the case where both the detergent and the sulfurized-phosphorized base were used than in the case where only the sulfurized-phosphorized lard oil inhibitor was used. An examination of the engine parts at the conclusion of the test showed, however, that the deposits were noticeably less in the case where the detergent was used than in the case where no detergent was used. Thus, although the detergent appears to somewhat detract from the inhibitory powers of the S-P base, it is, nevertheless, beneficial to the engine to use detergent in conjunction with the base in order to prevent deposition of varnish on the working parts of Table III 180 via 180 vis. 15 0 vis Y itraight (st'agm) oil and .s% oil and .5 7 oil and 5% fig?" gent detergent detergent detergent Loss in weight of silver-cadmium bearing. 0. 796 0. 282 0. 344 0. 351 0.366 Loss in weight of copper-lead bearing 0. 080 0.158 0. 047 0.080 0. 224 Neutralization No 1i. 9 l. 13 3. l. 80 1. 82 Naphthainsoluble percent 1.62 0.22 l. 26 0.97 0. 55 Chloroiorm 1nsoluble.. do 1.24 0. l3 0. 62 0. l7 0. 38 Soluble sludge do. 5. 29 o. 69 '3. 58 1. 74

The same 180 vis. Pennsylvania neutral was the engine. This is particularly true in connecsubjected to the Chevrolet engine test without any inhibitor but containing 0.5% of the same detergent used in the Underwood tests and also with the detergent plus 1.5% of the S4 lard oil inhibitor previously described. The results are set forth in Table IV: I

Table I V 1 Gain.

The Chevrolet engine test is run as follows: The engine ,is operated at a speed of 3150 A ynamometer load is applied equivalent to 25 to 30 horsepower. The oil sump temperature is maintained at 280 F. plus or minus 2 F. and the cooling water out is maintained at 200F. plus or minus 2 F. The test is run for 66% hours sult more oxidation and varnish formation in the oil take place. With present compression ratios in spark ignition type automotive engines, the use of the detergent in conjunction with the sulfurized-phosphorized fatty base inhibitor'is not so essential since.oxidation, because of the small amount of blow-by, is almost entirely avoided by the sulfurized-phosphorized-lard oil base and therefore, varnish formation is not particularly troublesome. Thus, although' the sulfur'med-phosphorize fatty base cuts down sludge and varnish formation, there will be some amount of sludge and varnish formation, the amount depending upon the conditions of operation of the engine, the particular engine in connection with which the oil is used and the particular oil used. Deposition of this varnish on the working par s should be prevented by addition of a proper detergent in order to have the engine operate efliciently. It will be understood that detergents other than the specific detergent above named may be used and such detergents maybe added in amounts approximately those of the inhibitor.

A series of Timken and Y Faville-Levalley rial is an effective inhibitor when used in amounts below that at which it is an efiective ex- (Falex) tests were also run in order to indicate phosphorized fatty material has unusual properwhether or not the sulfurized-phosphorized base ties in imparting to mineral oils corrosion rehad any substantial extreme pressure load imsistant properties and resistance to acid, sludge parting characteristics when added to mineral and varnish formation. The inhibitor may be oil in small proportions. The results of these added to the mineral oil alone or to oils to which tests are given in the following table: have been added other materials such as deter- 7 Table V gents. Although I have found that the optimum amount ofinhibitor which should be added to k the mineral oil is between approximately 2-3% by volume, beneficial results may be obtained Oil gill in! B M Falcx with amounts as low as 0.1% by volume. The tests 32:, g: indicate that there is no advantage in adding in excess of 5% by volume of the inhibitor where Gun com on Found, Pound, the oil is to be used for lubrication of internal E. 90-; 2 2 I 153 combustion engines. Thus, it will'be seen that 12 61750 122 the sulfurized-phosphorized fatty material when 3.2 g 5.228 28% added to mineral oil lubricants in quantities so 18 101250 11750 small as to not be practicable as an extreme pres- ;-8 2g ggg @338 sure additive, is valuable in inhibiting corrosion 1 43 750 2:250 of bearings and in stabilizing the oil during use 18.0 6g 3g, M 8 5 in a motor and in connection with lubrication of (f5- 8 570 1' 525 other bearing surfaces.

L0 12 7, 250 1, 500 It is claimed: i2 i3 3;?23 238 1. A lubricant comprising mineral lubricating 3.0 18 8,750 1,000 11 and between 0.1 and 5% by volume of sulfur- ;8 g gag Z28 3o ized and phosphorized fatty material. 101 51 231000 21100 2. A lubricant in accordance with claim 1 in -0 68 3, 250 2, 200 which the fatty material is lard oil.

3. A 'lubricant in. accordance with claim 1 in An oil is not considered to-be a satisfactory which the fatty material is sperm oil. commercial extreme pressure lubricant unless it 4'. A lubricant in accordance with claim 1 in a will hold a pressure of at least 25,000#./sq. in. on v which the fatty material is rapeseed oil. the Timken machine and at least 2500 lbs. on the 5. A lubricant in accordance with claim 1 in Falex machine. It will be apparent, therefore, which the sulfurized and phosphorized fatty mathat the inhibitor is effective as such in amounts terial contains from 2% to 7% by weight of sulfur in which it has little value as an extreme presand from 0.11% to 0.56% by weight of phosphorsure additive. us.

Timken and Falex tests were also made on a 6. Th method of inhibiting corrosion of mesulfochl'orinated and phosphorized lard oil pre- 'tallic bearings and deterioration of lubricating pared in the manner previously described. The oils in service which comprises contacting said results are set forth in'I'able VI: bearing with mineral oils which normally tend to Table VI .Tmen at800 12% r. p. in. Oil $5 8 5 Falex max. load Inblend Beam Max. load press.

GglofcoastoilS.A.E. @236 1501: (journal sheared). 1 25 14,250 1,500: (brasspinsheared). 3 33 1 21, 250' 1,50 (brass pin sheared). 5 43 15,000 1,050 (brass insheared). 7 43 15,500 1,325 (wo d not hold 10 43 20,000 (would 'not hold 12 43 24,500 4,500: (0111 1mm 16 st 20,250 4,500fulllood. 1s 51 20,250 4,500: fullload r 5 4,200 5038 9 1 18 9,250 1, rasspin sheared). 3 33 13,000 1,000! rass insheared). 5 43 17,000 1,888 mssp shearer 7 43 20,000 1,000 grass pin shearecg 10 51 23,000 4,500 rasspm caret 12 51 20,000 4,500 brassplnsbearer) 16 5i .29,250 4,500 rassplnshearet) 18 51 31,000 4,500 (bran pin shearer) lubricant unlessvit will carry a load on the Tim kenhmachi zgabov'e 25,000#/sq. in. and above' 2500# on the File: machine, it willbe seen that corrode said bearing and to deteriorate during '.use, in the presence of from 0.1% to 5% by volume of sulfurized and phosphorized fatty material.

7. Method in accordance with claim 6 in which the sulfa-chlorinated phosphorized fatty 'mate- 7 the fatty material is lard oil.

f the fatty material is rapeseed oil.

10. Method in accordance with claim 6 in which the sulfurized and'phosphorized fatty material contains from 2% to 7% of sulfur and from 0.11% to 0.56% by weight of phosphorus.

11. The method of lubricating internal combustion engineswhich comprises contacting the moving parts thereof with a mineral lubricating oil containing suflicient sulfurized and phosphorized fatty material to inhibit oxidation of said oil but insufiicient to materially increase the viscosity of said oil.

12. Method in accordance with claim 11 in which the sulfurized and phosphorized fatty material is present in amounts of 0.1% to 5% by volume.

13. Method in accordance with claim 11 in which the fatty material is lard oil.

14. Method in accordance with claim 11 in which the fatty material is sperm oil. 1

15. Method in accordance with claim 11 'in which the sulfurized and phosphorized fatty material is prepared by reacting a fatty body with sulfur chloride and with a reactive phosphorus compound.

16. Method in accordance with claim 11 in which the sulfurized and phosphorized fatty material contains from 2% to 7% by weight of sulphorus.

1'7. Method in accordance with claim 11 in which the sulfurized and phosphorized fatty material is prepared by reacting lard oil with sulfur at elevated temperature and then reacting the sulfurized lard oil with a phosphorus containing material capable of chemically uniting phosphorus with the sulfurized lard oil.

18. A lubricant comprising mineral lubricating oil, between 0.1% and 5% by volume of sulfurized and phosphorized fatty material and a small amount of a detergent.

19. The method of lubricating internal combustion engines which comprises contacting the working parts of said engines with mineral lubricating oil in the presence of a small amount of sulfurlzed and phosphorized fatty material and a small amount .of a detergent.

20. Method in accordance with claim 19 in which the sulfurized and phosphorized fatty material is present in amounts of from 0.1% to 5% by volume of the oil.

21. A lubricant in accordance with claim 1 in which the fatty material is sulfurized by reacting between approximately 3% and 15% of sulfur halide therewith.

22. Method in accordance with claim 6 in which the fatty material is sulfurized by reacting 

